Conventionally at the present time discrete sensors are employed for measuring flow and the composition of respiratory gases, and furthermore other quantities such as for instance pressure, more particularly in intensive care and anesthesia and also in general medical diagnostics. The flow of respiratory gas is measured using various different techniques as for example by a pneumotachograph or by means of anemometry at a respiratory tube or in a respirator. The different gas concentrations of respiratory gas are determined, in a manner independent thereof, predominantly in the shunt or, partly, in the main flow using different principles, for example by infrared spectroscopy, paramagnetism or mass spectroscopy. The gas pressure in the respiratory passages is again separately measured at the mouth or in the respirator. Owing to the different measuring arrangements delays in time occur between the individual signals for the measured values, In most cases the signals are not measured directly at the mouth, but at other positions so that it is difficult to see the timing thereof in relation to the breathing of the patient, In the case of gas determination in the shunt flow there are furthermore transients, which are responsible for errors in the accuracy of measurement. Moreover, the methods are frequently intricate and expensive when employed in combination.
As employed in hospitals such measuring equipment is involved in the treatment of several patients each day so that there is the danger of cross infections between them.
One object of the present invention is consequently the provision of an apparatus for the measurement of respiratory gas parameters in accordance with the preamble of claim 1, in the case of the respiratory gas parameters are simultaneously measured.